I was wondering how to easily install Steam on Debian Wheezy and unexpectedly found solution on GitHub. To download and play Linux games available on Steam without any hassle you need to download and install Steam installer for Wheezy package.
Steam store contains several interesting games but do not expect much at this moment.
I tried several games without any problems although only simpler ones due to integrated graphics card.
I do not plan to use Steam as I do not have enough time to play games but it is interesting to see how things change nowadays.